tools: Remove absolute_import in most tools.

Tweaked by tabbott to not remove it from lister.py, linter_lib, and
friends, since those are intended to support both Python 2 and 3
(we're planning to extract them from the repository).

tools/test-queue-worker-reload

@@ -1,7 +1,6 @@
 #!/usr/bin/env python3
 
 from __future__ import print_function
-from __future__ import absolute_import
 
 import os
 import sys